Semiconductor backplanes for AMOLED displays lager than Smartphone's are today limited to amorphous silicon, its derivative Low Temperature Poly Silicon (LTPS), and so-called Oxide or IGZO. Amorphous silicon, the dependable material for Flat Panel Displays (FTD) including today's Large Screen TVs, are LCD displays. However, a-Si with its low electron mobility of about 1 cm2/V-sec, is not suitable for OLED displays, which are current-driven devices, requiring low impedance semiconductors.
The industry has turned to two alternatives for AMOLED displays, laser-crystallized a-Si, generally referred as LTPS, and Oxide (IGZO). LTPS has nearly 100 times the electron mobility, and very adequate for OLED backplanes. It has been overwhelmingly adopted for AMOLED Smartphones, but its high defectivity rate has limited its use to this application, and the LTPS panel sizes for small displays like I-PODS, is slowly emerging.
Increasingly IGZO, with an electron mobility of about 30 cm2/V-sec, is another choice for OLED in larger display formats, including televisions, mainly because the ability to form large monolithic coatings of great uniformity. For this reason, it is often said IGZO is akin to a-Si, in its ease and cost of fabrication. In fact several companies have developed large IGZO-based Televisions. But uniformity in coating thickness does not translate into uniformity, and stability, on threshold voltages and other critical parameters. Lately (in 2015) a large display manufacturer has encountered serious financial problems betting on IGZO.